Transmission



A. Y. DODGE July 21, 1942.

' TRANSMISSION Filed Sept. 25, 1940 5 Sheets-Sheet 1 QN NN INVENTOR. H12/EL )f DODGE www M96 M ATTORNEYS.

July 21, 1942.

A. Y. DQDGE TRANSMISSION Filed Sept. 25, 1940 3 Sheets-Sheet 2 ATTORNEY Patented July 21,' 1942 UNI-'ra STATES `miam" rrFic ateatro TRANSMISSION Adiel Y. Dodge, Rockford, Eil.

Application September 25, 1940, Serial No.` 358,321

215 claims.' (Cl. 'I4-189.5)

This invention relates to transmissions and more particularly to transmissions for motor vehicles and the like.

It is one of theobjects of the invention to provide a transmission which is iniinitely variable through one or more speed ranges and which provides for relatively high engine speeds Athen-obiectdrelate to the provision of a transmission in which free wheeling is pre-V vented, in which the drag at idling speeds is reduced, which permits the engine to turn up to a higher stall speed, and which Voperates at high ,meiiicieneyfthroughout its entire speed and torque lange.

The above and other objects, advantages and Ilet ends of the vanes 29.

' of the torque converter approaches unity. M

direction about their pivoted 'mounting by reaction of the driving liquid and centrifugal weights 26 tend to turn them in the opposite direction.

A rotor sleeve or hub 28 carries a set' of vanes 31B adjacent the outlet ends of the vanes 24 and a second set of vanes 32 adjacent the in- Between the sets of vanes and 32 there is arrangeda set of stator vanes 34 carried by a hub 36 which is mounted on an extension of the xed easing i6 by a combined one-way brake andbearing 38 which may be of 'the type disclosed and claimed in my Patent No. 2,113,722. By this means the stator is prevented from turning backwards but is permitted to turn forwards as the driving ratio torque converter herein has been illustrated more or less diagrammatically but it will be understood that it might take the form of any of` the torque converters more particularly described and claimed in any of my copending apnovel features of the invention will be apparent y from the following description of the accompanying drawings, in which:

Figures 1, 2, 3 and 4 are axial. sections with parts in elevation of four transmissi bodying the inven 1s an enlarged partial view of an automatic clutch.

The transmission of Figure lconnects a driving shaft I0 which may be the crank shaft of an internal combustion engine to a driven shaft4 I2 which may be connected to the rear wheels of an automobile or to any other mechanism to be driven either directly or through a gear set such as is shown in Figure 2. As shown the driving shaft l0 has an extension I4 journaled at one end in the shaft I2 to maintain the shafts in alignment.

VThe transmission includes an outer stationary casing I6 coaxial with the driving and driven shafts within which is arranged an in- 'nitely variable speed torque multiplying unit shown as `a hydraulic torque converter indicated generally at I8. The torque converter includes an impeller casing 20 secured to the driving shaft I0 and'carrying a setl of xed impeller vanes 22. Adjacent the outlet end of the vanes 22 asetl of vanes 24 are pivoted in the casing plications Serial Nos. 3,544, filed January 26, 1935, 57,520, filed January'fi, 1936, or 95,117, led August 10, 1936, or that any other desired type of infinitely variable torque multiplying yunit might be employed.

The transmission further includ arp anetary gear set comprising a ar 40 connected to a supportlmeinlr/inwhich is splined to the o or sleeve 28 and has a sleeve extension 44 around the driven shaft I2. If desired a friction brake 4I may be provided to engage the ring gear to brake the transmission. 'Ihis is particularly desirable when the shaft I2 is connected to a shifting gear unit to facilitatel shifting. The driven shaft I2 is provided with a flanged extension forming a gear carrier 46 mesh with the ring gear 40 and with a sun gear 50 carried by a sleeve 52 which is rotatable on theshaftextension I4. A one-Way clutch and bearing 54 is provided between the sleeve portion 44 and the shaft I2 -to prevent the portion 44 from over-running theshaft I2 forwardly. A similar clutch member 55 maybe provided between the sun gear 50 and the driving shaft extension I4 to prevent free wheeling if desired. This clutch member prevents the sun gear from over-running -the driving shaft forwardly.

In order to connect the sun gear drivably to A- thev shaft extension I4 there is provided accord- 20. The vanes 24 tend to be turned in one 55 ing to the present invention a coiled clutch member 58 wrapped around and secured at one end to the sun gear sleeve s2. The shaft u carries an ofl'set sleeve member 68 drivably keyed thereto and having a portion 62 surroundlng and spaced slightly from the clutch member 58.

AIn operation the driving shaft turns theim-4 peller casing 22 and through liquid contained therein drives the rotor 28` at an increased torque as is well understood in the art. This turns the ring gear supportl 42 and the sleeve 44 forwardly and drives -the driven shaft |2 forwardly through the clutch 54. At low speeds, since both the ring gear and the gear carrier 46 are turned forwardly at the speed of the rotor 28, the planetary gear set lwill turn as -a unit and the'driven shaft will be driven directly through the torque converter I8. At this time the clutch 58 is disengaged and the clutch 56 is inactive since the sun gearr 58 is turning at a lower speed forward than the driving shaft I4.

As the speed increases, centrifugal force acting on the clutch 58, will expand it into engagement with the sleeve 62 and the friction drag thereon will wrap it tightly against the sleeve 62. This establishesa driving connection in the forward direction between the shaft I4 and the sun gear 58. Thereafter the driven shaft is driven through the planetgears 48 jointly by th'e ring gear 48 and the sun gear 58inr-twcrpatlis of power iiow as described in my application S'aNorso-through'rthegearset 723,083, filedV April 30, 1934, and in my Reissue Patent No. 20,846. At this time the clutch 54 overruns since the driven shaft is normally turning faster than the ring gear 48.

If the driven shaft I2 should tend to overrun ratios could be provided if desired or that other types of shifting units could be provided.

The parts are shown in the neutral position in which there is no driving connection between shafts I2 and 92. To start, the gear 86 may be shifted into mesh with gear 86, brake 4| being engaged to facilitate this operation if desired. The drive initially is through the fluid clutch to the member 42, through clutch 54 to shaft I2 and gear 16, to gear 18 and sleeve 88 and gear 86 to gear 86 and sh'aft 92. Thus at the start the drive is directly through the iiuid clutch to the gear 16 vand since the clutch may be made smaller than usual due to the novel combination with the gear set a higher engine speed at starting is provided.` The smaller clutch alsol reduces drag at idling speeds so that the gears need not be disengaged on a stopping.

As the speed increases the clutch 58 will engage the sleeve 62 to connect th'e driving shaft extension I4 with the sun gear 58. At this time twopath drive is provided so that the uidglhth/ of transmission in which one element of the gear the drivinghagas inhoastingmhhillonthewsetisconnected directly to the driving shaft and like the clutch 58 would lterni to release. This would produce a condition of free wheeling and if.

it is desired to prevent such operation, a clutch such as 56 may be provided. This clutch will prevent the sun gear 58 from overrunning the driving shaft -I4 so that the driving and driven shafts will be connected through the transmission at all times and overrunning of the driven shaft will be resisted by the torque converter. e

Figure 2 illustrates another type of transm.s

sion in which a fluid flywheel or clutch is emthe impeller of the hydraulicunit is driven by another element of the gear set.A As shown, 'a

' driving shaft ||8 is connected to a gear carrier ||2 rotatably supporting -a plurality of planet gears ||4. 'I'h'e gears II4l mesh with a ring gear I6 connected by a frame work.||8 to the impeller or driving member |28 of a hydraulic torque converter. The torque converter as shown includesa rotor or driven member |22 and a stator |24 held against reverse rotation by a one-way ployed in place of the torque. converter of Flgure 1. Since a. great many of the are identical with those of Figure 1 they have been indicated by the same reference numbers.

As shown the driving shaft I8 is connected to an impeller casing 64-of a uid flywheel. Rigid vanes 66 and pivoted vanes 68 controlled by weights 1.8 are mounted in the casing 64 and cooperate with rotor vanes 12 on a rotor hub 14 to-- form a fluid circuit. l'Ihe hub 14 is splined to the ring gear supporting member 42. This construction forms a fluid flywheel or clutch" whose action is well known in the art.

The shaft I2 is shown carrying a gear 16 meshing with a gear 18 which is formed on a'sleeve 88 rotatable on a lay shaft 82. The sleeve'88 also carries gears 84, 86 and 88 of different sizes, the gear 88 meshing with the usual reverse idler 88. An output or driven shaft 92 is arranged coaxially with the shaft I2 and has slidably spline'd thereon two sh'iftable gears 94 and 86 which are controlled by shift rods 88 throughforks |88. The gears 16 and 94 are provided with mating clutch teeth |82 through whichthey may be connected for direct drive. 'T' s The illustrated shifting unit is a conventional type providing three forward speeds and reverse hut it will be understood that more or less speed brake |26.

'I'he planet gears ||4 also-'mesh with a sun pinion |28 formed on a sleeve which is rotatable ori an extension of the driven shaft |38. The sleeve is formed with "two v'sets nof clutchteeth |32 and |34 meshing respectively with the cutiff teeth |36 and |38. 'Th'e teeth |36 are carried by sliding blocks |31 slidably mounted on the gear carrier ||2 and urged inwardly into engagement with the teeth |32 by springs |48. Below a predetermined speed the springs |48 hold the teeth |36 in engagement with the teeth |32 to connect the gear carrier and the sun gear. Above 9. predetermined speed centrifugal force on the blocks |31 is suiiicient to overcome the springs |48 and when the pressure on the clutch teeth is relieved temporarily, as for example by'temporarily slowing-down th'e driving engine, the blocks |31 will move outwardly to disconnect the gear carrier and the sun gear.

The clutch teeth |38 are carried by a block or sleeve |42 splined on the driven shaft |38'. A spring |44 urges the sleeve |42 to the right as shown in Figure 3 normally to disengage' the clutch teeth |34 and |38. Preferably a spring detent |46 is provided normally tending to Ihold the sleeve |42 in either its right or left hand position. The sleeve |42 is shifted by means of centrifugal weights |48 engageablewith an angular surface on the sleeve and an angular surface on a fixed flange |50. As the weightsv|48-move out under the inuence of centrifugal force they cam i locked out by the clutch teeth |32-and |36 and turns` as a unit so that `the impeller |20 is driven at the same speed as the driving shaft H0. The impeller turns the rotor |22 which is keyed to the driven shaft so that the driven shaft is driven hydraulically at an increased torque. As thev speed increases, the sleeve |42 first tends to move to the left to bring clutch teeth |38 into engagement with clutch teeth |34. Meshing of these teeth, however, is prevented due to the ejection angle thereon. At about the same speed or a slightly higher speed the blocks |31 tend to move outwardly, but'are held in their engaged position by the .pressure on the clutch teeth. At this time if the torque load is temporarily relieved, as for example by temporarily closing the engine throttle, the blocks |31 will move cut and the sleeve |42 will move to the left.

At this time the driving shaft' ||0 drives the gear carrier and the torque thereon is divided,

a part of it flowing tothe ring gear ||6 and theimpeller |20 through the hydraulic unit to the driven shaft while the remainderA of the torque from the planet pinions goes directly to the sun gear |28 and through clutch |34 and |38 to the driven shaft. Thus a two-path flow of torque is provided similar to that described above inconnection with Figure 1. At this time the impeller is caused to turn at speeds above that of the shaft due -to shaft |30 and sun gear |28 turning slower than shaftA l0, the speeds of the Several elements becoming the same as the ratio between the driving and drivenshafts approaches unity. Figure 4 shows a somewhat different` arrangement employing a regenerative or run around power circuit at low speeds. Since a number of the parts in this construction are substantially similar to those of Figure 3,' like reference numerals have been used to indicate the corresponding parts. As shown in this construction, the gear carrier H2 is connected to the drive shaft ||0 and is formed with a ange -|52 connected through a one-way clutch |54 to the rotor |22.

'I'his clutch prevents the rotor from turning forwardly faster thanthe driving'shaft, but enables the driving shaft to overrun the rotor. The rotor isalso fomedwith a flange |56 formed with'a series of clutch teeth |58 adapted to mesh with the clutch teeth |36 on the blocks |31. In this case the blocks |31 are normally urged inwardly by the springs |40 vand Vare urged outwardly by centrifugal force, g j

t The construction of the speed responsive clutch formed by the blocks |31 and flange |56is better illustrated in Figure 5. As shown in this iigure the teeth |58 are formed with an ejection angle' and the outer end of the teeth |36 are formed with a similar ejection angle. Thus when the ange |56 is overrunning the ring gear ||5 in a clockwise direction the teeth will be held out of engagement until their speeds are subtive engagement of, the clutch once it starts in response to centrifugal force a spring detent |60 is preferably provided engagingA a notch |62 in the block |31. This detent tends to hold the block in its radial inward position until centrif-V ugal force becomes sufficiently great to cam the detent inwardly against the spring |40, the parts f being so proportioned as to insure that this eX- cess forceis suiiiciently great to move the teeth |36 completely into engagement with the teeth |58 after synchronization.

In operation of the embodiment shown in Figure 4,'the driving shaft drives the .gear-carrier ||2 forwardly and the ring gear ||6 connected to the driven shaft acts as a fulcrum so that the sun gear |28, which is connected to the impeller |20, will be turned forwardly at an increased speed. The impeller tends to turn the rotor |22 forwardly at increased speed but this is prevented by the one-way clutch |54 as a result of which rotation oftthe impeller is resisted. This re' sistance reacting; back on the sun gear, tends to cause the ring 'gear H6 and the driven shaft |30 to be turned forwardly at reduced speed and increased torque.

When the speed of the ring gear becomes suf.

ciently high the clutch |36 will move into engagement with the clutch teeth |58 to connect the d riven shaft and the rotor |221 At this time the torque is divided in the planetary gear set, a part of the torque on the planet pinions ||4 going directly to the gearjl I6 and driven shaft while the remainder of the torque goes through the sun gear |28 and the hydraulic unit to the driven shaft. At this time the regenerative circuit is replaced by a two-path power ow circuit of the non-regenerative type as described in connection with Figure 3`. This transmission provides an extremely wide range of operation and is highly desirable for some installations in which K diierence of range is n'eeded.

While several embodiments of the invention have been described in detail, it will be understood that other types of infinitely variable torque transmitting units or either regenerative or nonregenerative differential gears might be employed and that numerous other changes might be made. The embodiments illustrated are therefore 'not intendedas a definition of the scope-of the invention, reference being had for this purpose to v'the appended claims.

` This application is a continuation in part of my copending application Serial No. 283,582, led July 10, 1939.

What is claimed is:

1. A transmission comprising an infinitely var-' iable speed, `torque-transmitting unit having a driving member and a driven member, a differential gear set having one element connected to the driven member, a driven shaft connected to another element of the gear set, one way drive' meansconnecting said one element to the drivenl shaft, and means responsive to the speed of a third element of the gear set to connect said third element to the driving member.

2. A' transmission comprisingan innitelv variable speed,'torque-transmitting unit having a.

driving memberganda driven member, a differential gear set having one element connected to the driven member, a. driven shaft connected to another elementof the gear set, releasable'drive means connecting said one element to the driven shaft, and disengageable means for connecting a third v ber.

element of the gear set -to the driving mem- 3. A transmission comprising an` infinitely variable speed, torque-transmitting unit having a driving member and a driven member, a differential gear set having one element connected to the driven member, a driven shaft connected t another element of the gear set, one-way drive means connecting said one element to the driven shaft, disengageable'means for connecting a third element of the gear set to the driving member,

` and a one-way clutch for connecting said third element to the driving member to prevent the third element from overrunning the driving member.

4. A transmission comprising an infinitely variable speed, torque-transmitting unit having a driving member and a. driven member, a differential gear set having one element connected A to the driven member, a driven shaft connected to another element'of the gear set, one way drive `means connecting said one element to the driven shaft, and one-way clutch means connected to a third element of the gear set and engageable with the driving member above a predetermined speed of said third element and through. which the driving member drives the third element.

5.- A transmission comprising an infinitely variablel speed, torque-transmitting' unit having a the driven shaft, speed responsive means for connecting the ,sun gear of the gear set to the driving member above a predetermined transmission speed, and a one-way clutch for preventing the sun gear from overrunning the driving member.

9. A transmission for connecting a driving shaft to a driven shaft comprising an infinitely variable speed, torque-transmitting unit having a driving member connected to the driving shaft and a driven member, a one-way clutch connecting the driven member to the driven shaft, a differential gear set having one element connected to the driven member and another element connected to the -driven shaft, and speedl A ing the driven member to the driven shaft, a

driving member and a driven member, a differential gear set having one element connected to the driven member, a driven shaft connected to another element of the gear set, one-way drive means connecting said one element tothe driven shaft, one-way clutch means connected to a third element of the gear set and engageable with the driving member above a predeterminedA speed of said third element and through which the driving member drives the third element, and a second one-way clutch between the third element and tlfe'driving member to prevent the third element from-overrunning the driving member.

6. A transmission comprising an infinitely vardriving memberK and a driven member, a differen- `tial gear set having one element connected to the driven member; a driven shaft connected to differential gearv set having one element connected to the driven member and another eiement connected to the driven shaft, and means responsive to the speed of a third element of the gear set for connecting said third element to Ithedriving sh'aft to be driven thereby in a forward direction.l

11. A transmission for connecting a driving shaft to a driven shaft comprising an infinitely variable speed, torque-transmitting unit having a, driving member connected to the driving shaft and a driven member, a one-way clutch connecting the driven member to the driven shaft, a-diiferential gear set having one element connectedfto the driven member and another iable speed,torquetransmitting unit having a y element connected to the driven shaft,/a sleeve secured to the drivingv shaft, and a coiled clutch element secured at one end to a third element of the gear set and lying within said sleeve to another element of the gear set, one-way drive Y means connecting said one element to the driven shaft, a spiral clutch element connected at one fend to a third element of the gear set,'and a sleeve secured to the driving member and surrounding said clutch element, whereby the clutch element will be thrown out in response to cen' trifugal force vabove a predetermined speed` of the third element t'o connect the sleeve and driving member`to the third element.

7. A transmissioncomprising an infinitely variable speed, torque-transmitting unit having a driving member and a driven member, a plan,

etary gear set having its ring gear connected to kthe driven member, a driven shaft connected to the planet carrier of said gear set, one-way drive means connecting the ringgear and driven shaft through which the ring gear may directly drive the driven shaft, and speed responsive means forconnecting the sun gear of thegear setto the driving member above a predetermined transmission speed.

8. A transmission comprising an infinitely variable speed, torque-transmitting unit having a driving member and a driven member, a planetary gear set having its ring gear connected Ato the driven member, a driven shaft connected to the planet carrier of said gear set, one-way drive means connecting the ring gear and driven shaft be expanded -against the sleeve by centrifugal force, thereby connecting the driving shaft and the third elment.-

- 12. Atransmission for connecting a driving shaft toa driven shaft comprising an infinitely variable speed, ytorque-t'ransmitting unit having a driving member connected to the driving shaft and adriven member, a one-way clutch connecting the driven member to the driven shaft, a

planetary gear set having its sun gear formed with an elongated hub rotatable on the driving -shaft and its other elements connected respectively to -the driven member and the driven shaft, a coiled clutch element on said hub, and av sleeve secured to the driving shaft andA surrounding said clutch element, said clutch element normally clearing the-sleeve but being movable into driving engagement therewith in response to centrifugal force.V

13. A transmission -for connecting a driving n shaft to afdriven shaft comprisinganinflnitely variable speed, torque-transmitting unit having a driving member connected to the driving shaft and adriven member, a one-way clutch connecting the driven member to the driven shaft, a planetary gear set having its sun gear formed with an'elongated hub rotatable on the driving shaft and its other'elements connected respectively to the driven member and the driven shaft, a coiled clutch element on said hub.' a

v sleeve secured-.to the driving shaft and surroundthrough which the ring gear may directly drive 'I/liing said clutch element, lsaid clutch element normally clearing the sleeve but being movable into driving engagement therewith in'response to centrifugal force, and a one-Way clutch between the sun gear and the driving shaft to prevent the sun gear from overrunning the driv ing shaft.

14.. A transmission for connecting a driving shaft to a driven shaft comprising a hydraulictorque transmitting device including an impeller connected to the driving shaft and a rotor, a one-way clutch connecting `the rotor to the driven shaft, a differential gear set having one element connected to the rotor and another element connected to the driven shaft, and means responsive to the speed of a third element of the gear set to connect'the third element to the driving shaft.

:15. VA transmission for connecting a driving shaft to a driven shaft comprising a hydraulic torque transmitting device including an impeller connected to the driving shaft and a rotor, a one-way clutch connecting the rotor to the driven shaft, a differential gear set having one element connected to the rotor and another element 'connected to the driven shaft', means responsive to the. speed of a third elementof the gear set to connect the third element to the driving shaft, and one-way clutch between thethird element and the driving shaft to prevent the third element from overrunning the driving shaft.

16. A transmission for connecting a driving shaft to a driven shaft comprising an infinitely variable speed torque-multiplying unit having a driving member connected to the driving shaft, a driven member, and a reaction member transmitting device forming a fulcrum for torque multiplication, a

differential gear set having one element connected to the driven member, one-way drive means between said one element and another element of the gear set to drive said other element forwardly, said other element being connected to the driven shaft,. and disengageable means for connecting a third element of the gear set to the driving shaft.

17. A transmission for connecting av driving shaft to a driven shaft comprising a hydraulic torque converter having a vaned. impellerconnected to the driving shaft, a vaned rotor, and a vaned stator forming a fulcrum for torque multiplication, a differential gear set having vune element connected to the rotor, one-way drive means between said one element and another `element of the gear set to drive said other element forwardly,

said other element being connected to the driven shaft, and disengageable means for connecting a third element ofthe gear set to the driving shaft..

18. A transmission 'for connecting driving and driven shafts comprising a hydraulic Atorque to one of the shafts, a differential gear set, means- 5 able clutch means connected to said one element of the gear set and `operable in response to the speed thereof to establish one` set of driving conditions through the transmission, and a second automatically operable clutch for connecting a third elemen't of the gear set to the other of said members to establish a. different set of driving conditions through the transmission.

20; A transmission for connecting driving and driven shafts comprising a hydraulic torque havingdriving and driven members, a differential gear set, means connecting one element of the gear set to thedriving shaft, means connecting another element of the gear set to said driving member, said driven member being connected to the driven shaft, speed responsive clutch means connecting the drivingl shaft to a third element of the gear set below a predetermined speed of the driving shaft, and speed responsive clutch means connecting said third element to the driven shaft above said predetermined speed.

21. A transmission forv shaft to a driven shaft differential gear set,`a hydraulic torque transmitting device including a vaned impeller and a vaned rotor forming a toroidal liquid circuit, means connecting said rotor to the driven shaft, means connecting one element of the gear set to the driving shaft, means connecting another element of the gear set to the impeller, and clutch connecting a driving means operable when engaged to connect a third element of the gear set to the driven shaft.

22. A transmission for connecting a driving shaft to a driven shaft comprising a planetary differential gear set, a hydraulic torque transmitting device including a vaned impeller and a vaned rotor forming a toroidal liquid circuit,- means connecting said rotor tothe driven shaft,

means connecting one element of the gear set to the driving shaft, means connecting another element of' the gear set to the impeller, and

clutch means operable in response to the speed of the driven shaft to connect a third element of the gear set to' the driven shaft.

23. A transmission for connecting a driving shaft to a. driven shaft comprising a planetary differential' gear set, a hydraulic torque transmitting device including a vaned impeller and a vaned rotor forming a toroidal liquid circuit, means connecting Asaidrrotor to the driven shaft, means connecting one element of the gear set to the driving shaft, means connecting another element of the gear set to the impeller, clutch means providing a. mechanical connection vfor direct drive between the driving shaft and the impeller,.and a second clutch means to connect a third'element of the gear set to the driven,

shaft'.

24. A transmission for connecting driving and driven shafts comprising a hydraulic torque transmitting device having driving and driven members, a' differential gear set, means connectconnecting vone element of the gear set to one Aof the shafts, means connecting another element of the gear set to the other of said members, and disengageablemeans for connecting a-third element of the gear setto the other ofthe shafts.

19. A transmission for connecting driving and I driven shafts comprising a hydraulic torque transmitting device having driving and driven members, a differential gear set, the driving shaft being connected to one element of the gear set, means connecting another elemento! the gear set to one of said members, automatically opering one 'element of the gear set to one of said members, means for connecting another element of the gear set to th other of said members, one of s'aid connecting means being a disengageable clutch, means connecting one of the lshafts to a third element of the gear set, means connecting one of said members to the other shaft to provide a two-path drive throughthe transmission when said clutch is engaged, and clutch means for providing a mechanical connection for direct drive lbetween said one of the shafts and the niember'othexthan the last named one of I comprising a planetary f said members to provide a single path drive through the hydraulic device.`

' 25. A transmission fory connecting driving and driven shafts comprising a hydraulic torque converter having a vaned driving member, a vaned driven member and a vaned stator forming a fulcrum for torque multiplication, a diierential gear set, means connecting one element of the gear set to one of said members, means for connecting another element of the gear set to the other of said members, one of said connecting o single path drive through the hydraulic device.

ADIEL Y. DODGE. 

